Biochemistry, Mutation

Excerpt

Deoxyribonucleic acid (DNA) is a double helix composed of two strands of four types of nucleotides. Each nucleotide consists of the sugar deoxyribose, a nitrogenous base, and a phosphate group. These four nucleotides include adenine (A), thymine (T), cytosine (C), and guanine (G). They always pair together with the same partner; adenine pairs with thymine (A-T), and cytosine pairs with guanine (C-G). This allows base pairs to be replaced, repaired, or replicated and not ruin DNA’s backbone and subsequent information. This information is derived from the precise order of these base pairs, and as two strands compose every DNA molecule, each strand contains the same coding information. The two strands are joined together via hydrogen bonds between nucleotides, and they run antiparallel to one another. One strand goes from 5’ to 3’ and the other from 3’ to 5’, defined by numbering from deoxyribose’s carbon atoms.

Genes, in turn, are a sequence of nucleotides that serve as the basic unit of heredity and code for a specific product, either protein or RNA. The cell relies on genes to be accurately and fully copied, transcribed, and translated to create a functioning product, often a specific protein but occasionally RNA as well. However, genetic sequence mutation can occur, which refers to an unintended alteration in a gene’s coding.

Mutations can reduce functionality or limit the expression of the gene product, potentially damaging or even killing the cell. Genetic mutations, whether acquired or inherited, form the basis for many disease states, cancer, and aging.